For any error relating to the file system, I would start by backing-up any vital files you may have (in case the file system becomes unusable) and then run an integrity check on the disk. As in ... right-click drive C: in Windows Explorer, select Properties, select the Tools tab and then select the Check Disk option. You can let it go without fixing anything if you simply want to get the facts first or you could tick the box to 'fix' any problems found, but make sure you have that backup first. You will probably be prompted to do the check at next boot, which is fine, so reboot and let it go.
In many cases, I have found that is all that's needed to fix a file system error. It is at least a place to start. HTH.